What is anesthesia?

Anesthesia is a state that one enters during surgery, during which they are rendered unconscious.

Anesthesia refers to a reversible, drug-induced loss of sensation that is necessary for many medical procedures. It is often used to provide comfort for patients undergoing surgery. Anesthesia is made as safe as possible when performed by trained professionals.

Anesthesia in general controls pain during a surgical procedure. Monitoring and the use of drugs are used to prevent pain, cause amnesia, and control vital signs during the operation. An anesthesiologist takes control of your pain and controls your hemodynamics during the procedure. Anesthesia will relax the patient, block pain, cause sleep, and create an unconscious state during surgery. 

Anesthesia is a loss of feeling or awareness caused by drugs or other substances. Anesthesia keeps patients from feeling pain during surgery or other procedures. Local anesthesia is a loss of feeling in one small area of the body. Regional anesthesia is a loss of feeling in a part of the body, such as an arm or leg. General anesthesia is a loss of feeling and a complete loss of awareness that feels like a very deep sleep.

This answer is based on source information from National Cancer Institute.

The term anesthesia comes from the Greek for "loss of sensation." That is not the only effect it has on your body. Anesthesia, a reversible condition induced by drugs, results in one or more states of being. It can relieve pain, give amnesia to knock out the memory of the procedure or how it felt, it can reduce anxiety (who doesn't have anxiety when undergoing a medical procedure?) it can also paralyze muscles.

It sounds scary, but anesthesia is made as safe as possible with careful calculation of the required dosages. Medical professionals monitor the procedure diligently. Not all anesthesia types are created equal.

When you think of anesthesia, you likely think of what's called general anesthesia, when you're completely unconscious during major surgery or similar medical procedures. But there are several types, not all of them leave you oblivious to the world. Local anesthesia can affect just a small patch of skin. The type you receive depends on several factors, including the medical procedure you need and your medical history. There can also be overlap between types of anesthesia. Often, more than one drug is necessary to produce the desired effects.